Fatty acid and soap derived from mineral oil and process of making same



Patented Dec. 11, 1928.

UNITED sTATEs PATENT OFFICE.

GELLERT ALLEMAN, OF SWARTH'MORE, PENNSYLVANIA, ASSIGNOR IO SUN 'OIIICOM- -IPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF NEW JERSEY.

FATTY ACID AND SOAP DERIVED FROM MINERAL OIL AND PROCESS OF MAKING SAME.

No Drawing.

In the manufacture of lubricating oils ond distillate may then beredistilled, the part remaining also being adapted for lubricatingstock. Lubricatingstock is usually treated with sulfuric or othersuitable acid, with ag tation, forming an acid sludge, whlch 1s drawnoff. After the sludge is separated from the lubricating stock, thelatter is treated with caustic soda or any other alkali, forming aprecipitate, which may be called soda sludge or alkali precipitate,whlch is drawn'off and usually allowed to go to waste.

It is known that this alkali precipitate con- 20 tains a fatty acid soapor organic acid soap,

:1, large proportion of mineral oil, a considerable'body of inertmaterial similar to the fossil resins, which I hereinaftercall'petroleum resins, some sodium sulfate, and more or less water. Itis known to so treat this alkaline precipitate as to eliminate some ofthe mineral oil, a large part of the water and most of the salts, and'tomaterially reduce the percentage of mineral oil. However, no process hasever been devised to effect an absolute, or even a substantial,elimination of the mineral oil, except the process set forth in myapplication filed February 6, 1924, Serial No. 691,022; norhas anyprocess been devised to separate the petroleum resins.

In other words, a mineral oil derivative soap that. is miscible in allproportions with water or mineral oil, that is not a sulfonic acid soapor a naphthenic acid soap and is adapted to undergo the character ofhydrolytic decomposition that occurs with soaps of animal or vegetableorigin, that is distinguishable from soaps of animal or vegetable originin that it contains a substantial proportion of mineral oil andpetroleum resins and a minute percentage (say .02 per cent) of sulfur,is known (see Maitland Patents 1,425,882 and 1,425,884) but no suchproduct is known that is also'devoid of both mineral oil and petroleumresins; and no such product is known that is devoid of mineral oilexcept the product set forth in my said application.

,undergo the character of hydrolytic decomeral oil and petroleum resins.Such isolated Application filed July 18, 1925. Serial 110. 44,629.

So, also, it is known to provide a saponifiable mineraloil derivative,or fatty acid, that is not a. sulfonic or naphthenic acid, and which isa liquid practically odorless, insol- I uble in water and does notbecome rancid, and

which is saponifiable and when saponified 1s soluble or emulsifia'ble inall proportions with water and mineral oil and is adapted to positionthat occurs with soaps of animal and vegetable oil, and whichisdistinguishable from soaps of animal or vegetable origin in that itcontains a substantial proportion of mineral oil and petroleum resins aswell as a minute percentage of sulfur (see Maitland patents aforesaid);but no such product is known that is also devoid of both mineral oil andpetroleum resins; and no such product is known that is devoid of mineraloil except the roduct set forth in my said application.

T 1e object of my invention is to isolate the above described fatty acidand soap derived from mineral oil; or, more accurately stated, toproduce -a fatty acid and a soap having the characteristics specifiedabove as characterizing known fatty acids and soaps but which issubstantially devoid of both minfatty acid product, as might beconjectured, I found to be a mixture of acids. The pre I ponderatingproportion of these fatty acids have certain compositions and propertieswhich, combined, characterize no known isolated fatty acid derived fromany source whatever. i

In practicing my process, I may start with any composition derived frommineral oil and containing soap, petroleum' resins and .90 mineral oil,such as the alkali precipitate hereinbefore mentioned or the product ofthe Maitland patents specified. In giving a specific example of theprocess, it will be understood that the statements therein contained asto the precise details of treatment are predicated upon the treatment ofa composition having definite proportions of certain ingredients andproduced in the above described treatment of lubricating oil stockderived from Texas oil. It will also be understood that even with thisparticular crude pe-. troleum, different distillation processes, andeven variations in the same distillation process, as well as variationsin the crude oil, would yield alkali precipitates of varied compositionsand characteristics, making advisable some variation from the specificexample of the process herein given, in order to secure the eliminationof the mineral oil and petroleum resins to the highest degree. Theskilled operator, however, can readily adjust the factors to secure themain results sought, namely, the substantially complete elimination ofthe mineral oil and petroleum resins.

A typical soap emulsion (e. g., alkali precipitate or soda sludge) fromwhich I have succeeded in eliminatin the mineral oil and petroleumresins, is as ollows:

Per cent. Soap 11.6 Petroleum resins 17 .1 Mineral lubricating oil 46.Sodium sulfate 2.3 Water 23.

The soap, oil, and water emulsion, or colloidal suspension, containsparticles or droplets which are positively charged. If this mixture istreated with gasoline, practically no separation takes place, exceptafter very long standing. If, however, a small amount of ,lithiumsulfate, sodium sulfate or potassium sulfate, or a small amount oflithium chloride, sodium chloride, or potassium chloride is added to thesuspension or emulsion in gasoline, an immediate separation takes place.The sulfates are found to be superior to the chlorides, the doublenegative charge on the sulfate ion being more effective than the singlenegative charge on the chloride ion in neutralizing and precipitatingthe positively charged emulsion particles. Lithium salts are superior tosodium salts, and sodium salts superior to those of potassium. This is afunction of surface tensionlithium increasing surface tension more thansodium or potassium, and hence tending to break the emulsion morereadily. From a commercial standpoint, sodium chloride (common salt),becauseof its abundance and low cost, seems to be the most desirablesubstance to effect the separation of the gasoline and oil,withdissolved resins, from the soap, water and a minor proportion ofresins. A saturated solution of the .salt is used, being added to theamount of 10 per cent of the total volume. The salt solution may beadded before the introduction of the asoline or it may be added afterthe gaso ine has been distilled into the soap-oil-water emulsion.Instead of using a saturated solution of salt in water, solid sodiumchloride (salt) may be added.

It is best to allow the gasoline to enter the crude soap tank, at thebottom, as a vapor. This stirs the mixture, and probably also aids inneutralizing the electrical charges on the suspended colloidalparticles. Larger surfaces are exposed to the gasoline, in this manner.

The apparatus employed is conveniently arranged as follows: An upright,cylindrical container is employed to hold the oil-soapwater emulsion,which should fill the container to about one-third its capacity. This isconveniently connected to a gasoline still. The bottom of the firstmentioned container should be above the level of the gasoline still.Vapors of gasoline are passed through appropriate pipes, from the still,to the bottom of the container holding the soap-oil-water emulsion. Tothe emulsion is added a saturated solution of common salt, equivalent involume to about one-tenth of the soap-oilgasoline emulsion. Gasolinevapor is introduced at the bottom until the container is almost filledby the condensed gasoline. The introduction of gasoline into thiscontainer is then discontinued and the mixture allowed to separate. Thegasoline-oil layer on top is siphoned back into the-gasoline still andthe process repeated. After about three extractions, the soap-watersolution which remains in the bottom of the container is substantiallyfree of mineral oil, but contains the petroleum resins that have notbeen dissolved by the gasoline.

The partially purified soap contains the original sulfur compounds,wholly or principally sodium sulfate, which were In the crude soap.These can be largely removed by known methods if their removal bedesirable. For example, the soap solution may be concentrated by firstevaporating some of the water (to expedite the operation) and thencooling in order to separate the soap from the sodium sulfate, whichremains in solution in the water. The separation begins to take place atabout5 C. and is hastened by lower temperatures. The sodium sulfateremains in solution in the water.

The soap has the characteristics hereinbefore described ascharacterizing a known product, i. e. that of the Maitland patentspecified, but has the further characteristic n that it is devoid ofmineral oil and of the majof part of the resins. If it is desired toconvert the soaps into fatty acids it may be so converted bymeanseffective to convert other soaps into fatty acids, as, for example, 5 bydecomposing the soap with sulfuric, hydrochloric or other mineral acids.These fatty \acids have an acid number of about 103.55 (The originalcrude soap before treatment yields fatty acids having an acid number of30.) j-

The fatty acids are now subjected to distillation at an absolutepressure of 4 mm. of mercury yielding distillates which are free fromresins. Up to a temperature of 180. C. a fraction is obtained having anacid number of 187.06. The next fraction boiling off between 180 and 190C. has an acid number of 174.4. The next fraction boiling ofl' between190 and 200 C. has an acitl'nu'mber 13c of 160. The residue, containingmost of the resins, present before distillation, has an acid number of61.

Any of these fractions may be, of course, saponified by the addition ofany agent adapted to saponify fatty acids. If the fatty acid having anacid number of 103.5 is so treated, it of course, produces a soap thesame as that from which the fatty acid was directly derived bydecomposition with a mineral aci My improved fatty acids differ fromordinary fatty acids of animal or vegetable origin having chemicalcompositions and molecular weights approximating those of my im-' provedfatty acids in that they are liquid at ordinary temperatures aridsolidify only at very low temperatures, differ in refractive index andby their degree of volatility (distilling temperature under a vacuum),and do not dry or harden when exposed to air but remain sticky or tackyindefinitely. At any rate, they haverbeen exposed to observation for aperiod of eighteen months and still retain this quality.

In order to more particularly differentiate my improved fatty acids fromknown fatty acids, the following more specific informa tion regardingthe compositions, qualities, and properties of the same are given.

1. A predominating proportion of the acids belong to the series C H Oand G H O One acid out of eleven that have been isolated from themixture of acids seems to belong to the series C H O 2. They do notabsorb oxygen from the air, and do not dry, or harden.

3. They have an extremely low melting point (below minus 30 C.)

4. They are extremely viscous at low temperatures and will not flow at 0C.

5. The salts of all the acids are soluble in gasoline, in ether, and incarbon tetrachloride. The lithium, ammonium, potassium, sodium, andmagnesium salts are soluble in water.

6. The acids cannot be distilled at ordinary atmospheric pressurewithout decomposition.

7. At an absolute pressure of 4 millimeters of mercury, the acidsvolatilize at temperatures ranging between about 160 C. and 245 C.

8. They have an extremely high refractive index. This ranges between1.48563 and 1.49654. Only two of these acids have a refractive indexbelow 1.49, and only one has a refractive index below 1.48968.

9. They are not volatile with steam ;.that is, when the materials areheated to a temperature above the boiling point of water but to atemperature below the point at which they will volatilize, and steam ispassed through the materials, at the bottom of the container. the fattyacids will not pass over with the steam.

- 10. Their carbon content ranges froni C to C that is, there are from16 to 25 carbon atoms in a molecule of the acid.

11. Their molecular weight ranges from about 250 to about 376. p a I 12.The saponificat-ion numbers obtained indicate that there is but onecarboxyl group present.

.13. They latter belong to the series C H O 14. They do not give thereactions of ketonic acids.

In place of using gasoline in the manner described, I may use any lighthydrocarbon, whether derived from petroleum or other sources, such as abenzol distillate from coal tar. Y

are notnaphthenic acids, which" It is not my intention, however,- tolimit the product herein claimed to a product produced by the describedprocess,'inasmuch as other methods of producing the fatty acidsdescribed may be devised. The described method, however, is particularlyadvantageous, particularly in respect to its simplicity and economy, andis entirely eflicient to effect the desired isolation of the fatty acidsoap, from which all mineral oil and petroleum resins may be practicallycompletely eliminated by practicing the described process in a thoroughand careful manner.

Where, in the claims, I refer to soap or fatty acid substantially freeof resins, I do not mean to be confined 'to a product from which theresins are necessarily completely eliminated. The fact that resins arepresent in the residue from the distillation indicates their presence,in small proportiomin the fatty acids before distillation. It isobviousthat the advantages of my new product are 1 present, to asubstantial'degree, even though J I the original content of resins 1Svery greatly v reduced rather than absolutely eliminated.

Having now fully described my invention, what I claim and desire toprotectby Let tors-Patent is: i

1. As a new product, a mixture of fatty acids derived from mineral oil,the same being insoluble in water and readily saponifiable, and whensaponified being miscible. in all proportions with mineral oil and waterand when mixed with oil and water forming a, homogeneous emulsion andhaving essential characteristics of soaps of animal or vegetable originin that it forms with water a similar emulsion and undergoes the samecharacter of hydrolytic decomposition; the fatty acids beingdistinguishable from othe. saponifiable derivatives of mineral oil inthat in addition to the characteristics Specified they are substantiallyfree of mineral oil and petroleum resins, and being distinguishable fromfatty acids of animal or vegetable origin in that they have a meltingrange. below minus 30 C. v

2. As a new product, a mixture of fatty range below minus 30 0.

acids derived from mineral oil, the same being substantiall free frompetroleum resins and mineral oi, and a preponeratmg proportion of whichhave the generic formulae C H O, and 0,,H and a melting volatilize at anabsolute pressure of four mil- *limeters mercury at temperatures rangingbetween about 160 0. and about 245 0.,

have refractive indices mostly above 1.49,

have carbon contents the molecules of which contain from 16 to carbbnatoms and molecular weights ranging from about 250 to about 376.

4. As a new product, a derivative from mineral oil, the same being asoap miscible in all proportions with water and mineral oil, and whenmixed with mineral oil and water forming a homogeneous emulsion, andhaving essential characteristics of soaps of animal and vegetable originin that it forms with water a similar emulsion and undergoes the samecharacter of hydrolytic decomposition; the new product beingdistinguishable from soaps of animal or vegetable origin in that thefatty acids from which the soap is derived have a melting range of belowminus 0. and being distinguishable from other soaps derived from mineraloil in that in addition to the characteristics specified it issubstantiall free of both mineral oil and petroleum reslns.

5. As a new product, a mixture of fatty acids derived from mineral oil,the same bein insoluble in water and readily saponifia 1e, and whensaponified being miscible in all proportions with mineral oil and waterand when mixed with oil and water forming ,a homogeneous emulsion andhavin essential characteristics of soaps of animal or vegetable originin that it forms with water a similar emulsion and undergoes the samecharacter of hydrolytic decomposition; the fatty acids beingdistinguishable from other saponifiable derivatives of mineral oil inthat in addition to the characteristics specified their acid number isnot below about 100, and being distinguishable from fatty acids ofanimal or vegetable origin in that they have a melting range of belowminus 30 0.

6. A soap derived from mineral oil and comprising a saponified mixtureof fatty acids having an acid number not below about 100 and a meltingrange of below minus 30 0., the soap being miscible in all. proporofhydrolytic decomposition; I

7. As a newproduct, the. hereinbefore de-' scribed mixture of fattyacids derived from 0., 0 not absorb oxygen from the air, cannot bedistilled at at-' mospheric pressure without decomposition,-

tions with mineral' oil and water and when mixed with oil andfwaterforming a homogeneous emulsion and hav' teristics of soaps of anima orvegetable'origin in that it forms witkwaler a similar emulsion andundergoes the. same character mineral oil, the same being insoluble inwater and readilysa onifiable, and when saponified bein with mineral oiand water and when mixed with oil and water forming a homogeneousemulsion and having essential characteristics of soaps of animal orvegetable'origin in that it forms with water a similar emulsion andundergoes the same character of hydrolytic decomposition; the fattyacids'being distinguishable from other saponifiable derivatives ofmineral oil in that in addition to the characteristics specified theiracid number is not below about 160, and being distinguishable from fattyacids of animal or vegetable origin in that they have a melting range ofbelow minus 30 C.

8. A soap derived from mineral oil and comprising a saponified mixtureof fatty acids having an acid number not below about 160 and a meltingrange of below minus 30 0., the soap being miscible in all proportionswith mineral oil and water and when mixed with oil and water forming ahomogeneous emulsion and havin essential characteristics of soaps ofanima or vegetable oriemulsion and undergoes the same character ofhydrolytic decomposition.

9. As a new product, a mixture of fatty acids derived from mineral oil,a preponderating proportion of which have the generic formulae C H O and0n H O and have a melting range below minus 30 degrees 0. and are sonearly pure that their acid num ber is not below about 100. V

10. As a new product, a soap comprisinga saponified mixture of fattyacids as specified in claim 9.

11. As anew product, a mixture of fatty acids derived from mineral oil,a preponderating proportion of which have the generic formulae 0,,H,,,,O and CDH O and having a melting range below minus 30 degrees 0., andare so nearly pure that their acid number is not below about 160.

,12. As a new product, a'soap comprisin a saponified mixture of fattyaclds as speci ed in claim 11 13. The process of recovering fatty acidsfrom a crude soap emulsion containing soap,

mineral oil, petroleum resins and water which comprises adding to thecrude soa emulsion a water soluble salt in quantity su ficient to enablethe hereinafter specified sepessential characmisci le in all proportionscontact therewith, the gasoline dissolving the oil, separating thesolution of gasoline and such of the resins as are dissolved thereinfrom the soap, converting the soap into fatty acids, and by distillationseparating the fatty acids from any of the resins-that have notdissolved in the gasoline In testimony of which invention, I havehereunto set m hand, at Swarthmore, Pennsylvania, on thls 10th day of July, 1925. v

1 GELLERT ALLEMAN.

